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. 2025 Apr 8;5(5):100790.
doi: 10.1016/j.xops.2025.100790. eCollection 2025 Sep-Oct.

A Comparative Validation Study of Near Visual Acuity Assessment Using Different Handheld Acuity Charts

David Ziyou Chen  1   2   3 , Yih-Chung Tham  2 , Liang Shen  4 , Soon-Phaik Chee  1   3   5   6   7
Affiliations

A Comparative Validation Study of Near Visual Acuity Assessment Using Different Handheld Acuity Charts

David Ziyou Chen et al. Ophthalmol Sci. .

Abstract

Objective: To develop a conversion table and compare the cross-validity of 3 types of widely utilized near vision charts: the ETDRS near chart, the N-notation chart, and the Rosenbaum chart.

Design: A prospective, cross-sectional, comparative validation study.

Participants: Aged ≥40 years.

Methods: A conversion table for the 3 types of near charts was created using objective character sizing based on vertical height captured using a surgical microscope with a 10× magnification. Eligible presbyopic patients had their near vision tested sequentially with 3 near charts in a randomized order.

Main outcome measures: Pearson correlation coefficient (r) for the relationship among the near visual acuity charts. The consistency between the different charts was evaluated by Bland-Altman diagrams.

Results: A total of 204 participants (129 women, 63.2%) were recruited for the study (mean age, 58.9 ± 7.1 years). For correlation, r ranged from 0.596 to 0.836 (all P < 0.001). The Rosenbaum chart had the smallest range of difference against the ETDRS chart (standard deviation [SD] = 0.12), followed by the N-notation chart (SD = 0.15). Most of the converted logarithm of the minimum angle of resolution (logMAR) values from the N-notation and Rosenbaum charts were between 0.0 and 0.1 higher than the ETDRS logMAR equivalent (range: 0.07-0.11), with a tendency for both the N-notation and Rosenbaum charts to overestimate logMAR at more positive values.

Conclusions: We have developed a conversion table for 3 types of commonly used near vision charts. When compared with the ETDRS near chart, the Rosenbaum chart had a smaller range of difference than the N-notation chart. Both the Rosenbaum and N-notation charts tended to underestimate near vision at worse vision.

Financial disclosures: The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Keywords: ETDRS near chart; N-notation chart; Near visual acuity; Presbyopia; Rosenbaum chart.

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Figures

Figure 1
Figure 1
Objective grading of various reading charts with a surgical microscope. The reticule centers on the character being used for objective measurement: (A) 20/200 character on the ETDRS chart by Alcon; (B) 20/200 character on the ETDRS chart by Bausch & Lomb; (C) J16 character on the Rosenbaum chart; and (D-E) N24 characters on the alphabetical and numerical N-notation charts, respectively.
Figure 2
Figure 2
Bland−Altman plots of N-notation and Rosenbaum charts against ETDRS-A and ETDRS-BL as reference. Various Bland−Altman plots depicting comparisons between (A) ETDRS-BL against ETDRS-A, (B) ETDRS-A against N-notation chart letters, (C) ETDRS-A against N-notation chart numbers, (D) ETDRS-A against Rosenbaum chart numbers, (E) ETDRS-BL against N-notation chart letters, (F) ETDRS-BL against N-notation chart numbers, and (G) ETDRS-BL against Rosenbaum chart numbers. ETDRS-A = ETDRS chart by Alcon; ETDRS-BL = ETDRS chart by Bausch & Lomb; logMAR = logarithm of the minimum angle of resolution.
Figure S1
Figure S1
A photo of 2 optotypes from the N6 row of the N-notation chart taken from the microscope. Due to printing ink variability, the heights of these optotypes are not uniform the bases of the optotypes are not horizontal.
See this image and copyright information in PMC

References

    1. GBD 2019 Blindness and Vision Impairment Collaborators Vision loss expert Group of the global burden of disease study. Causes of blindness and vision impairment in 2020 and trends over 30 years, and prevalence of avoidable blindness in relation to VISION 2020: the right to sight: an analysis for the global burden of disease study. Lancet Glob Health. 2021;9:e144–e160.
    1. Bourne R.R.A., Flaxman S.R., Braithwaite T., et al. Magnitude, temporal trends, and projections of the global prevalence of blindness and distance and near vision impairment: a systematic review and meta-analysis. Lancet Glob Health. 2017;5:e888–e897. - PubMed
    1. GBD 2019 Blindness and Vision Impairment Collaborators Vision loss expert Group of the global burden of disease study. Trends in prevalence of blindness and distance and near vision impairment over 30 years: an analysis for the global burden of disease study. Lancet Glob Health. 2021;9:e130–e143.
    1. Tiraset N., Poonyathalang A., Padungkiatsagul T., et al. Comparison of visual acuity measurement using three methods: standard ETDRS chart, near chart and a smartphone-based eye chart application. Clin Ophthalmol. 2021;15:859–869. - PMC - PubMed
    1. Vasavada V., Vasavada S.A., Shastri L., et al. Visual outcomes comparing emmetropia vs mini-monovision after bilateral implantation of a nondiffractive extended vision intraocular lens: randomized trial. J Cataract Refract Surg. 2024;50:799–804. - PubMed

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